I purchase a OPENVPN from PUREVPN service provider and they offer port forwarding which means the allow their VPN ip's address to be accessed anywhere

When I installed it directly on my Windows PC through OpenVPN it works very well and I was able to access my website and RDP outside my internet but when I install it on er605 through OpenVPN Client, it is not accessible outside the network and it opens the er605 login page, Could it be firewall problem from the er605 or er605 doesn't allow this. Please someone should help.